An important and growing part of the textile industry is the medical and related healthcare and hygiene sectors. Textile materials used in medical-related applications include, for example, surgeon""s gowns, caps and masks, patient drapes, bandages, wipers and cover cloths of various sizes. Such textile materials, however, are conductive to cross-infection and transmission of diseases caused by microorganisms. As such, the possibility of spreading infections caused by the lethal HIV virus, the insidious hepatitis virus or other epidemic diseases has created an increased concern regarding the use of protective facilities and uniforms for workers in the medical/healthcare/hygiene sectors. Currently, textile materials used in medical applications are disposable, nonwoven synthetic fabrics that are neither biocidal nor reusable. Such textile fabrics provide protection by blocking the transmission of microorganisms, rather than by inhibiting the growth of the microorganisms. Thus, cross-infection through surface contact of the contaminated textile fabrics is problematic. As a result, in an effort to prevent the cross-infection and transmission of diseases, the contaminated materials must be appropriately sterilized and discarded after use. Unfortunately, such sterilization and discarding procedures result in substantial increases in the cost of healthcare and in the amount of bio-hazardous wastes that are generated.
Accordingly, it is desirable that bacterial infections resulting from contact with contaminated textiles be reduced or eliminated, and that transmission of pathogenic bacteria from person to person during wear or use of contaminated textiles be prevented by inhibiting the growth of the microorganisms on fabrics. Moreover, it is desirable that surgeon""s dresses, hospital carpeting and bedding materials, underwear, socks, and uniforms be biocidal so as to provide the best protection possible. In addition, it is desirable to have biocidal textiles for use in, inter alia, hotel-use towels, bedding materials, socks and other hygienic products as well.
Currently, there are two general categories of technologies that can provide protection for medical/healthcare/hygiene personnel. They are (1) physical techniques which involve the formation of a physical barrier against microbial infiltration or transmission by selecting fabric constructions and coating that are impermeable or that are microporous and contain antimicrobial agents; and (2) chemical technologies which involve the incorporation of active functional agents onto fabrics or fibers by grafting or other chemical methods. Disposable materials are examples of the first category. The coating method involves the application of impermeable materials onto the surface of fabrics, thereby blocking the infiltration and permeation of microorganisms. However, cross-infection and spreading of diseases through the contact of the coating surface is still feasible and, thus, pose potential threats to workers who handle the contaminated materials. Moreover, the impermeable properties can cause wearers to become uncomfortable and, in turn, to become less efficient in their.
As such, the chemical association of antibacterial agents onto either the surface or entirety of the material appears to be more practical in terms of durability and efficacy of the antibacterial properties. There are two major pathways to chemically achieve durable antibacterial effects. In one pathway, the slow releasing of biocides through contact with the processed fabrics is employed. In this pathway, a pathway widely used around the world, sufficient chemical agents are impregnated onto the fibers by either chemical or physical methods. Thereafter, the biocides are slowly released from the processed fabrics into the media, thereby contacting and inhibiting the growth of microorganisms. Unfortunately, such chemical agents can be washed away easily if they are not covalently impregnated onto the surface of the fabrics. Moreover, the antibacterial functions are non-regenerable.
In the second pathway, a more innovative technology is employed which involves chemical modification of textile materials with biocidal or potential biocidal compounds, wherein the antibacterial properties of such compounds are regenerable with simple washing. The potential antibacterial groups can be rendered biocidal after washing with certain common chemicals, such as diluted bleaching solutions. Over thirty-five years ago, Gagliardi, et al. first proposed the regeneration principle of antibacterial finishing, hoping to regenerate the lost function by washing the used fabrics with some specific solutions (see, Am. Dyest. Reptr., 51, 49 (1962). However, although much effort has been expended, no commercial products have resulted.
In addition to textiles, food contact articles are another source of bacterial contamination. Multiple outbreaks of foodborne bacterium such as E. coli 0157: H7, have made people increasingly conscious of methods to control the spread of such bacterium. Food contact materials such as cutting boards, have long been suspected to be vectors for the spread of foodborne microorganisms. Thus, research has been focused on methods of managing the decontamination of cutting boards as a way to decrease foodborne illness.
Recently, good food hygiene practices as means of preventing foodborne diseases have taken on a new impetus. This is reflected in the USDA move to require safe handling labels on all raw meat and poultry. In the U.S. for example, Salmonella and Campylobacter accounted for 4 million cases annually, while total estimates of gastroenteritis ranged from 6-33 million cases (see, Todd, E., A Lancet Review, editors Waites, A. M., and Arbuthnott, J. P., London, pp 9-15, 1991). Although no firm epidemiological data exist as to how many of these result from inappropriate food handling, a researcher indicated that poor handling techniques in kitchens may be responsible for as much as 2-3 million foodborne outbreaks per year (see, Rubino, J., Foodborne Diseases in the Home, Seminar presented at the American Society for Microbiology General Meeting, New Orleans. 1996). Moreover, a recent Dutch report showed that 80% of Salmonella and Campylobacter infections arose from the home (see, Hoogenboom-Verdegaal, A. M. M. et al., Epidemiol Infect, 112:481-487. 1994). Considering that the World Health Organization believes that only 10% of actual cases are ever reported, the problem is indeed immense.
About 84% of all foodborne disease were due to bacteria and viruses, causing 9,000 deaths and costing $23 billion to the U.S. economy per year (see Rubino, supra). In Europe, it is estimated that between 50-80% of foodborne outbreaks occur at home (see, Sockett, P. N., In Encyclopedia of Food Science, Food Technology and Nutrition, ed. Macrae, R., Academic Press, London, pp. 2023-2031, 1993). One study showed that consumer knowledge of food preparation hygiene was very necessary. The occurrence of foodbome disease is on the rise; and in the developed countries at least, the majority of the salmonellosis and campylobacteriosis is occurring within the homexe2x80x94mostly due to inadequate food hygiene (see, Klontz et al., J Food Prot., 58:927-930. 1995).
Studies also indicate that of all of the causes that were involved, cross-contamination accounted for xcx9c30%, inadequate heating xcx9c45%, and inappropriate storage xcx9c40% (see, Rubino, supra). Studies in the UK showed that cross-contamination was responsible for 14% of human salmonellosis (see, Roberts, D. F., In Proceedings of the 2nd World Congress Foodborne Infections and Intoxications 1, Berlin, pp. 157-159. 1986). Indeed, it has become clear that this mode of contamination is much more serious than was previously thought and that the problem is indeed acute not only in the home but also in commercial food processing.
Sites and surfaces as vehicles of cross-contamination have been studied, particularly in Great Britain. In a British survey, moist areas such as the kitchen sink, waste traps and counter tops, as well as dishcloths and sponges, contained large numbers of enteric bacteria (see, Scott et al., J Hygiene, Cambridge, 89, 279-293. 1982). Preparation surfaces such as cutting boards were also implicated, containing and spreading pathogens even after washing and cleaning. Serological studies in outbreaks of infant salmonellosis often revealed the same serotype in all members of the family (see, Humphrey et al., Epidemiol Infect. 113:402-409 1994).
The main concern with food contact surfaces such as cutting boards is cross-contamination by foodborne or waterborne pathogens from all sources. Although the USDA, FDA, and National Sanitation Foundation allow use of closely grained hardwood for cutting boards, they recommend that plastic cutting boards be used in the kitchen because wooden boards are allegedly harder to decontaminate than plastic, due to wood""s inherent porosity. However, this recommendation may be too simplistic. Inherent characteristics of wood such as its superior grip, feel, and forgiveness to wear and tear on knife-edges make it attractive to users and preferable to plastic.
In view of the foregoing, there exists a need in the art for biocidal food contact materials and articles. The present invention remedies such need by providing, inter alia, biocidal food contact materials, surfaces and articles. The biocidal food contact surfaces reduce and eliminate cross-contamination of diseases and make wood surfaces safer. The biocidal surfaces inactivate microorganisms, keep the surfaces free of germs, as well as preventing the materials from building up biofilms.
The present invention provides, inter alia, durable and regenerable microbiocidal textiles and methods for preparing the same. Such textiles can be readily prepared using a classical wet finishing process to covalently attach a heterocyclic N-halamine to a cellulose based material or other polymeric material. Once prepared, the textiles of the present invention have a broad spectrum of biocidal activity against pathogenic microorganisms. Moreover, the biocidal activity of such textiles can be regenerated by washing with a halogenated solution.
In one embodiment, the present invention provides a process for preparing a microbiocidal cellulosic, cellulosic/polyester or polyester textile precursor, the process comprising: (a) immersing a cellulosic, cellulosic/polyester or polyester textile in an aqueous treating solution which comprises a heterocyclic N-halamine, a wetting agent and a catalyst; (b) removing the excess treating solution from the cellulosic, cellulosic/polyester or polyester textile; (c) drying the cellulosic, cellulosic/polyester or polyester textile; (d) curing the dried cellulosic, cellulosic/polyester or polyester textile; (e) washing the cured cellulosic, cellulosic/polyester or polyester textile to remove excess reagents; and (f) drying the treated cellulosic, cellulosic/polyester or polyester textile to remove water.
In another embodiment, the present invention provides a process for rendering a cellulosic, cellulosic/polyester or polyester textile microbiocidal, the process comprising: (a) washing a microbiocidal cellulosic, cellulosic/polyester or polyester textile precursor with a halogenated solution, the microbiocidal textile precursor being prepared in accordance with the above method; and (b) drying the treated microbiocidal cellulosic, cellulosic/polyester or polyester textile to remove water. In the process, the halogenated solution can be a chlorine solution or, alternatively, a bromine solution. In a presently preferred embodiment, the halogenated solution is a chlorine solution (e.g., a chlorine bleach solution such as Clorox). The washing of the microbiocidal cellulosic, cellulosic/polyester or polyester textile precursor with a halogenated solution renders the textile biocidal and, in addition, it sterilizes the textile.
In yet another embodiment, the present invention provides a composition for finishing fabrics, i.e., an aqueous treating solution, the composition comprising a wetting agent; and a heterocyclic N-halamine. In a preferred embodiment, the composition further includes a catalyst. In an even more preferred embodiment, the composition further includes additives (e.g., softeners and waterproofing agents) to impart favorable characteristics.
In another aspect, the present invention provides cellulose based composition comprising a cellulosic material; and a heterocyclic N-halamine covalently attached to the cellulosic material. The cellulosic material can be a wood material such as a wood, a wood fabric or a wood pulp. In certain instances, the wood material is a food contact material, surface or article. Various food contact materials, surfaces and articles include, but are not limited to, a plate, cookware, cutlery, a knife, a spoon, a cup, a table, a cutting board, a meat block, a baker""s top, a counter top, kitchenware and a floor. In a preferred aspect, the present invention provides durable and renewable biocidal wooden materials for safe food contact items and surfaces, such as cutting boards and containers, to be used in home kitchens and food processing industries.
Myriad applications exists for the microbiocidal textiles, or articles of the present invention. For instance, the microbiocidal textile materials can provide biocidal protective clothing to personnel in the medical area as well as in the related healthcare and hygiene area. In contrast to previously used textiles, the textiles of the present invention are not a barrier to microorganisms, but rather a disinfectant to them. As such, the regenerable and reusable biocidal materials can replace currently used disposable, nonwoven fabrics as medical textiles, thereby significantly reducing hospital maintenance costs and disposal fees. The microbiocidal properties of the textiles of the present invention can be advantageously used for women""s wear, underwear, socks, and other hygienic purposes. In addition, the microbiocidal properties can be imparted to paper or carpeting materials to create odor-free and germ-free carpets. Moreover, all germ-free environments, such as required in biotechnology and pharmaceutical industry, would benefit from the use of the microbiocidal textiles of the present invention to prevent any contamination from air, liquid, and solid media.
Other features, objects and advantages of the invention and its preferred embodiments will become apparent from the detailed description that follows.